Question

Let's look at the application of your concept in this example diagram in which we have 2 identical light bulbs, labeled A and B, connected in series with a battery and are illuminated equally.

There is a switch in the circuit that is initially open.

After we closed the switch, we'll see the bulbs in what state of brightness (I mean, ON or OFF,.....Bright or Dim?)

Answer 1

When two identical bulbs are connected in series then the same current will pass through the both of them. So, the power across both of them is given by

P =i²*R or P =V²/R

Higher wattage means less resistance, when a number of bulbs are connected in series, a bulb with lower resistance will consume less power & the potential diffrence across it will also be less. Therefore in series connection, a bulb with higher wattage will glow less brightly.

If both are having same watts means this will be ON condition and they are in bright condition.